boolean?

boolean

char?

character

number?

number

pair?

pair

port?

port

procedure?

procedure

string?

string

symbol?

symbol

vector?

vector

char-alphabetic?

alphabetic character

char-lower-case?

lower-case character

char-numeric?

numeric character

char-upper-case?

upper-case character

char-whitespace?

whitespace character

complex?

complex number

eof-object?

end-of-file object

even?

even number

exact?

exact number

inexact?

inexact number

input-port?

input port

integer?

integer

list?

list (use cheap-list? for faster processing)

negative?

negative number

null?

null

odd?

odd number

output-port?

output port

positive?

positive number

rational?

rational number

real?

real number

zero?

zero

hash-table?

hash table

boolean-or-symbol?

boolean or symbol

cheap-list?

list (use this instead of list? for faster processing)

color?

color

fraction?

fraction, as pair

grob-list?

list of grobs

index?

non-negative integer

list-or-symbol?

list or symbol

markup?

markup

markup-command-list?

markup command list

markup-list?

markup list

moment-pair?

pair of moment objects

number-list?

number list

number-or-grob?

number or grob

number-or-pair?

number or pair

number-or-string?

number or string

number-pair?

pair of numbers

rhythmic-location?

rhythmic location

scheme?

any type

string-or-pair?

string or pair

string-or-symbol?

string or symbol

void?

void

ly:book?

book

ly:box?

box

ly:context?

context

ly:context-def?

context definition

ly:context-mod?

context modification

ly:dimension?

dimension, in staff space

ly:dir?

direction

ly:dispatcher?

dispatcher

ly:duration?

duration

ly:event?

post event

ly:font-metric?

font metric

ly:grob?

graphical (layout) object

ly:grob-array?

array of grobs

ly:input-location?

input location

ly:item?

item

ly:iterator?

iterator

ly:lily-lexer?

lily-lexer

ly:lily-parser?

lily-parser

ly:listener?

listener

ly:moment?

moment

ly:music?

music

ly:music-function?

music function

ly:music-list?

list of music objects

ly:music-output?

music output

ly:otf-font?

OpenType font

ly:output-def?

output definition

ly:page-marker?

page marker

ly:pango-font?

pango font

ly:paper-book?

paper book

ly:paper-system?

paper-system Prob

ly:pitch?

pitch

ly:prob?

property object

ly:score?

score

ly:simple-closure?

simple closure

ly:skyline?

skyline

ly:skyline-pair?

pair of skylines

ly:source-file?

source file

ly:spanner?

spanner

ly:spring?

spring

ly:stencil?

stencil

ly:stream-event?

stream event

ly:translator?

translator

ly:translator-group?

translator group

ly:unpure-pure-container?

unpure/pure container